Means for securing flexible printing-plates



(No Model.) 2 Sheets-Sheet 1.

J. T. HAWKINS. MEANS FOR SEOURINGPLEXIBLE PRINTING PLATES. No. 427,320. a Patented May 6, 1890.

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J. T. HAWKINS. MEANS FOR SECURING FLEXIBLE PRINTING PLATES. No. 427,320.

Patented May 6, 1890.

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UNITED STATES ATENT OFFICE.

JOHN T. HAWVKINS, OF TAUNTON, MASSACHUSETTS.

MEANS FOR SECURING FLEXIBLE PRINTING-PLATES.

SPECIFICATION forming part of Letters Patent No. 427,320, dated May 6, 1890. Application filed May 16,1889. Serial No. 310,956. (No model.)

To all whom it may concern:

Be it known that I, JOHN T. HAWKINS, of Taunton, in the county of Bristol and State of Massachusetts, have invented new and useful Means for Securing Flexible Printing- Plates to the Beds, Cylinders, and Turtles of Printing-Machines, which invention is fully set forth and illustrated in the following specification and accompanying drawings.

The object of this invention is to provide means for securing comparatively thin'printing-plates upon either the fiat beds or cylindrical surfaces of printing-machin es, whether for relief-printing or by the lithographic method commonly known as zincographic printing.

The invention will first be described in detail, and then particularly set forth in the claims.

In the accompanying drawings, Figure 1 illustrates a broken vertical section of a flat bed, showing two modifications of the platestraining apparatus; and Fig. 2, a partial plan showing only one of the modifications of the straining apparatus. Fig. 3 shows a vertical section of a cylindrically-surfaced turtle with printing-plate attached. Fig. 4 shows a transverse section of a printing-cylinder on which a single thin printing-plate is strained into contact therewith by its two opposite ends, and Fig. 5 shows a partial plan of the same parts. Fig. 6 shows a transverse section of a cylinder carrying two printingplates having each a straining apparatus supplied to one end only, and Fig. 7 is a partial plan of the same parts. Fig. 8 illustrates a portion of a detached plate in two views, enlarged, showing the method of preparation of the plate. Fig. 9 shows a sectional view of grooved blocks or bars, enlarged, hereinafter particularly described.

In said figures the several parts are inclicated by reference-numbers, as follows:

The number 1 indicates the bed, turtle, or

cylinder, and 2 the thin printing-plate held in contact therewith.

In Figs. 1, 2, 3, 6, and 7 a grooved block or bar 3 is attached to one edge of the printingsurface of the bed, turtle, or cylinder, the groove 7 in which receives the tongues 8, formed along one edge of the printing-plate, and for the opposite edge of the printingplate a similar grooved block or bar 4 is attached to the free end of a straining-plate 5.

The straining-plate 5 may be jointed or fulcrumed to the bed, turtle, or cylinder, as shown near the central part of Fig. 1, or it may be formed as a thin elastic plate 5, secured at its fixed end to the bed, turtle, or cylinder by screws, as 6, or other suitable means, as shown at the right of Fig. 1 and in the other figures. The grooved blocks or bars 3 and 4 have the longitudinal groove 7, Fig. 9, cut in them at an acute angle with the surface upon which the plate rests, the groove being a little wider than the thickness of the plate to be held, so that the tongues 8 may enter it freely, and the'plate 2 has punched along its two opposite edges at any desired interval a line of tongues 8, which are bent in the act of punching to make an angle with'the plate corresponding with that of the groove 7 in the blocks 3 and 4..

The tongues 8 of the printing-plate may be of any suitable form, so that they may be bent upon a right line parallel with the edge of the plate, and not punched out on that line. In Fig. 8 at the left they are shown semicircular, as preferably made, and at the right as square in form, though octagonal or any desired form may be given to the free punched out parts of the tongues. The straining-screws 9 are tapped in the grooved blocks or bars 4, impinging against the metal of the bed, turtle, or cylinder, and the elastic character of the thin plate 5, when so constructed, or its fulcrum-pivot, when pivoted, as shown in part of Fig. 1, permits of the printing-plate 2 being strained at will by means of the screws 9.

With some very thin printing-plates it is to be understood that the elastic spring straining-plate 5, when used, may be adjusted to have an outward tension, which may be sufficient for the straining of such very thin printing-plates without resorting to the use of the straining-screws 9; but when the straining-plate 5 is fulcrumed or-jointed to the bed, turtle, or cylinder the strainin g-screws 9 must be used.

Having thus fully described my said improvements as of my invention, 1 claim- 1. In an apparatus for securing thin print- I oo ing-plates to the beds, turtles, or cylinders of printing-machines, the combination of a printing-plate having tongues, as 8, partially punched out within and at suitable distance from the edge of the same, so as to stand leading inward from said edge at an acute angle with said plate, grooved bars, as 4, carrying therein grooves, as 7, formed at a suitable angle for the reception of said tongues, secured to the free ends of mobile straining-plates, as 5, and straining-screws, as 9, substantially as and for the purposes set forth.

2. In an apparatus for securing thin printing-plates to the beds, turtles, or cylinders of printing-machinesthe combination of a printing-plate having a series of tongues, as 8, partially punched out Within and at suitable distance from two opposite edges of said printlug-plate, so as to stand leading inward from said edges at an acute angle With said plate, a grooved bar, as 3, having a groove, as 7, formed in it at a suitable angle for the reception of one series of said tongues, and secured to one edge of the printing-surface of said bed,turtle, or cylinder, and mobile strainingplates, as 5, to the free ends of which grooved bars, as 4, are secured by suitable strainingscrews, as 9, whereby said printing-plate is securely held and strained into close contact with said bed, turtle, or cylinder, substantially as and for the purposes set forth.

7 JOHN T. HAWKINS. WVitnesses:

J. F. HALEY, FREDERIC E. FISKE. 

